Often I will pick up interesting pieces of seashells while beach-combing. I’m getting better at identifying the pieces. The more variety of shells I collect, the easier it becomes. If the bit of shell baffles me at the seashore, I search it out in my favorite seashell book, or look through my seashell collection.
Seashells break for many reasons and some shells are more fragile than others. The Channeled duck clam is thin and most of them are broken on top. (It’s the white shell in the left-hand photo below.)
Usually it’s the surf and wave action that tumbles the shell until it breaks. Birds can be the culprits too. Whatever the reason, it can challenge the mind to picture bits as whole shells. Usually I am sorry I missed seeing it as a whole, beautiful specimen.
Pen shells (family Pinnidae) are usually gray or brown in color with an iridescent sheen. They are long and tapered in a triangular shape and most of the ones I’ve seen were on the east coast beaches in Florida.
They can be huge! My resource book says up to thirty-one inches in length! But many are found broken since they are a bit more fragile than an ordinary seashell.
The varieties found in Florida include the Saw-toothed pen shell, Stiff pen shell and Amber pen shell. The ones pictured here (photo by me) look like saw-toothed as they are smoother than the Stiff pen shell which has ridges with spines. Amber pen shells are lighter in color (hence the name).
Flag pen shells are wide and rounded on top and are found in the Indio-Pacific region.
The Noble Pen Shell (Pinna nobilis) has an unlikely history. It’s byssal threads (which anchor the shell in the sand when alive) were once used to make fabric. The threads were woven together to make what was known as “sea silk”. This large shell is found in the Mediterranean region and is in danger of extinction due to over use, pollution and decline in places for it to survive.
I don’t live on Sanibel and I haven’t even visited the Island in Florida for almost 20 years, but fortunately I know of a great blogger who lives there and shares her shelling knowledge with the world.
Recently she posted some photos of four small, similar-looking seashells that she had collected from the beach and without a keen eye, you may think they were all the same.
Pam does a nice job of pointing out the differences between the Mauve-mouth drill, Pitted Murex, Ribbed Cantharus, and the Gulf Oyster Drill. Go see!
The Shin-bone Tibia shell is quite unique looking. It averages close to eight inches in length (20 cm.) and has a long, thing, extension, or tail that is not usually seen on shells. The Tibia fusus also has distinct “teeth” that are clearly seen jutting out from the opening. The shell spirals to a point at the end and is tan and white.
One pretty seashell you may find if vacationing along coast of Florida is the lightning whelk (Busycon contrarium).
It is commonly found along the southern United States beaches from the Carolinas to Texas, and is the state shell of Texas.
I found the one pictured at the top of this article when I visited the Gulf Coast Sanibel Island area. Mine is only about 5 inches long, which is small compared to a full grown lightning whelk. They can grow to be nearly a foot and a half long!
The shell is easily recognizable by the tan or gray color with darker stripes and the fact that the opening is on the left side of the shell. It is one of the only gastropods (shells in one piece) to have this unique, sinistral aperture feature.
The lightning whelk lives in shallow, sandy areas and prefers warm water. This makes Florida the perfect location to call home.
It may be easier to collect an empty lightning whelk shell while visiting the gulf coast area. This is because Sanibel Island, located on the west coast, is known as one of the best shelling places in the world. But the lightning whelk can also be found on the East Coast. You may have to travel away from the ocean seashore to find one. The inner waterway / rivers are where I’ve found it.
I’ve come across lightning whelks on islands along the Intracoastal waterway. While boating and fishing, I usually get out and explore the muddy flats when the tide is low. This is an excellent time to find living sea life. Usually the shells are inhabited either by the mollusk or a hermit crab.
Below are a couple of photos of one such shell I found while walking the flats. This whelk had a pretty white top while the rest of the shell was more dark gray. I would have loved to collect it, but as you can see, the little guy who created that beautiful specimen was still using it as his home.
That yellowish hard piece is the operculum, or trapdoor, which shuts the snail inside the shell. It is made to fit perfectly within the aperture so no fleshy parts are exposed.
I always bring my camera because most of the shells I find offshore while boating contain living creatures. I seldom find anything but worn, broken shells to bring home.
A similar looking shell that I also find is the pear whelk. It has a very similar shape, but of course it’s opening is on the right, like most gastropod shells. So far, every one I’ve found has been home to a hermit crab.
Although the lightning whelk can grow to be very large, there is one that is even larger. The Florida horse conch can have the lightning whelk for dinner!
So what is the difference between a whelk and a conch? I intend to answer that soon.